1. Field of the Invention
The present invention relates to an optical information recording and/or reproducing apparatus in which optical information is recorded and/or reproduced with the aid of an information recording medium such as an optical card. In the apparatus according to the invention, the optical card and an optical head are moved relatively in a track direction, which is parallel to the extending direction of tracks formed on the optical card, to record optical information on the optical card and/or reproduce optical information recorded on the optical card; additionally, the relative moving speed between the optical card and the optical head is controlled at a given speed in order to prevent errors in recording and/or reproducing optical information on the optical card.
2. Prior Art Statement
On an optical information recording medium such as an optical card, it is impossible to re-write optical information in an area that has already been written thereon. But a an optical card has a great memory capacity, i.e. about several thousand times to ten thousand times as large as that of a magnetic card. The optical card has a memory capacity of about from one to two megabytes, so that a many applications such as a bankbook, a pocket map and a prepaid card for shopping can be considered.
Many optical card constructions have been suggested; and one of the constructions of the optical card, which has been suggested by the applicant in Japanese Preliminarily Laid-open Publication No. 63-37876, is shown in FIG. 1. On the optical card 41, there is provided an optical information recording portion 42. The optical information recording portion 42 comprises a plurality of tracks 43 which are formed in a longitudinal direction of the optical card 41, being parallel to each other. On both sides of the optical information recording portion 42, there are arranged ID portions 44 and 45, respectively. In each ID portion 44 and 45, address information corresponding to each track 43 is recorded. Since the ID portions 44 and 45 are provided on both sides of the optical card 41, the address information recorded thereon can be read out even when the optical card 41 is moved with respect to the optical head either from right side to left side or from left side to right side. As apparent from FIG. 1, the ID portions 44 and 45 are arranged inside by a given distance from both ends of the optical card 41 in order to prevent the influence of a defect or dirt formed on the edge portions of the optical card 41 and in order to relatively move the optical card and the optical head at a constant speed between ID portions 44 and 45. When recording and/or reproducing optical information on the optical card 41 from left to right, the address information recorded on the left side ID portion 44 is read out to identify the position of the optical head with respect to the optical card; and when recording and/or reproducing optical information on the optical card 41 from right to left, the address information recorded on the right side ID portion 45 is read out.
When optical information is recorded on the optical card 41 by the apparatus, the optical cards should be reciprocally moved in the track direction between the ID portion 44 and the ID portion 45 at a constant speed. While, in a clock pulse generating circuit equipped in the apparatus, clock pulses each having a given frequency are produced; and then optical information is recorded simultaneously with the clock pulses. It should be noted that the optical head may be arranged to move in the track direction instead of the optical card. On the other hand, when optical information recorded on the optical card 41 is reproduced, information reproducing signals are reproduced in accordance with the clock pulses.
In the conventional optical information recording/reproducing apparatus, the relative moving speed of the optical card 41 between the ID portions 44 and 45 is controlled with respect to the optical head to be kept at a given constant speed. However, there still remain a possibility that the relative moving speed between the optical card 41 and the optical head is greater than or lesser than the given constant speed for some causes. When such deviation of the relative moving speed is caused when optical information recorded on the optical card is reproduced, the pulses do not properly correspond to optical information pits formed on the information tracks of the optical card 41, so that information recorded on the optical card cannot be reproduced correctly. On the other hand, when such deviation of the relative moving speed is caused when optical information is recorded on the optical card 41, there can be the problem that optical information is recorded not only on the recording portion 46 but also on the ID portions 44 and 45. Particularly, in the optical card on which two ID portions are arranged on the both sides of the optical card, there is a great possibility of such a mistake.